Warming Up

How many words are in the following sentence?

The program works perfectly?

You will probably agree, that the sentence contains four words.

How many words are in the next sentence?

That #§&%$* program still doesn't work!\nI already 
de-bugged it 3 times, and still numpy.array 
keeps raising AttributeErrors. What should I do?

You may find the answer to this question less obvious. It depends on how precisely the special characters are interpreted.

What is automated testing good for?

Writing automated tests for your software helps you to:

• get clear on what you want the program to do.
• identify gaps in the requirements.
• prove the presence of bugs (not their absence!).
• help you during refactoring.